** Summary changed:
- IPU6 webcam (OV2740) stopped working after HWE upgrade to 7.0.0-15 on X1 Nano
+ IPU6 webcam (OV2740) on X1 Nano fails on kernel 7.0.0-14/-15: int3472 cannot
find GPIO chip INTC1096:00, VSC chain doesn't come up
** Tags removed: regression-update
** Description changed:
- Thanks in advance for taking a look.
+ Thanks in advance for taking a look. I've revised this description after
+ some follow-up testing; I think my original framing pointed at the wrong
+ thing.
- The webcam on my X1 Nano (Gen 2, OV2740 behind IPU6) worked on a clean
- Ubuntu 26.04 install. After a routine `apt upgrade` rolled the HWE
- kernel forward to 7.0.0-14 and then 7.0.0-15, it stopped producing
- frames. Nothing else camera-related changed in that upgrade.
+ What I'm seeing:
- On the surface everything still looks fine. libcamera and pipewire both
- see an `ov2740` device. /dev/video* are populated. The IPU6 driver is
- happy:
+ The webcam on my ThinkPad X1 Nano (Gen 2, OV2740 behind IPU6) currently
+ does not produce frames on either 7.0.0-14 or 7.0.0-15. libcamera and
+ pipewire both see an `ov2740` device, `/dev/video*` are populated, and
+ the IPU6 driver seems happy:
- intel-ipu6 0000:00:05.0: Found supported sensor INT3474:01
- intel-ipu6 0000:00:05.0: Connected 1 cameras
+ intel-ipu6 0000:00:05.0: Found supported sensor INT3474:01
+ intel-ipu6 0000:00:05.0: Connected 1 cameras
- But every app that tries to open the camera fails the same way:
+ But every app that opens the camera fails identically:
- spa.v4l2: /dev/video0: VIDIOC_S_PARM: Inappropriate ioctl for device
- spa.v4l2: '/dev/video0' VIDIOC_STREAMON: Link has been severed
+ spa.v4l2: /dev/video0: VIDIOC_S_PARM: Inappropriate ioctl for device
+ spa.v4l2: '/dev/video0' VIDIOC_STREAMON: Link has been severed
+ pw.node: (v4l2_input.pci-0000_00_05.0-110) suspended -> error (Start
error: Link has been severed)
- Cheese, Firefox, Chromium and Zoom all behave identically. BIOS privacy
- is off and the physical has been checked.
+ Cheese, Snapshot, Firefox, Chromium and Zoom all behave the same way.
+ BIOS privacy is ok and the physical toggle has been checked.
- I'm not sure I'm reading this right, but it looks like the VSC chain
- might not be coming up. `mei_vsc_hw` is loaded but unbound. `mei_vsc`,
- `intel_vsc`, `ivsc_csi`, `ivsc_ace` aren't loaded at all. The ov2740
- probe complains about missing rails (AVDD/DOVDD/DVDD, "supply X not
- found, using dummy regulator"), which I think the VSC normally provides.
+ The kernel-side warnings line up with what I'd expect if the VSC chain
+ never comes up:
- Tracing back, the ACPI path looks like:
+ int3472-discrete INT3472:05: cannot find GPIO chip INTC1096:00, deferring
+ int3472-discrete INT3472:06: cannot find GPIO chip INTC1096:00, deferring
+ ov2740 i2c-INT3474:01: supply AVDD not found, using dummy regulator
+ ov2740 i2c-INT3474:01: supply DOVDD not found, using dummy regulator
+ ov2740 i2c-INT3474:01: supply DVDD not found, using dummy regulator
- \_SB_.PC00.SPI1.SPFD HID INTC1094
- \_SB_.PC00.SPI1.SPFD.CVFD HID INTC1095
+ `mei_vsc_hw` is loaded but unbound. `mei_vsc`, `intel_vsc`, `ivsc_csi`,
+ `ivsc_ace` aren't loaded at all. The `INT3472:05/06` deferrals are the
+ chain that powers the OV2740 rails, which is presumably why ov2740 ends
+ up on dummy regulators.
- `INTC1094` is one of `mei_vsc_hw`'s alias matches. But the parent device
- for `\_SB_.PC00.SPI1` shows an empty `_HID` in /sys, so I don't think
- the kernel is instantiating a SPI controller on that node. If that's
- right, INTC1094 and INTC1095 never become spi_devices and `mei_vsc_hw`
- has nothing to bind to. That's my best guess at where it falls over, but
- I could easily be off.
+ What I now believe could be a more interesting (frustrating?) bug than a
+ kernel-version regression:
- A couple of side notes in case they matter:
+ * The camera **was** working on my stock 26.04 install on 2026-04-23.
+ * That install pulled in `linux-image-generic-hwe-26.04 → 7.0.0-14.14`. The
same `.14` deb is still installed today.
+ * `linux-firmware` is still at `20260319.git217ca6e4`, libcamera at 0.7.0-1,
pipewire/wireplumber at 1.6.2-1 / 0.5.13-1 — none have been upgraded since
install (per `/var/log/apt/history.log` and `/var/log/dpkg.log`).
+ * BIOS is unchanged (N3IET53W 1.33, 2025-12-03), `fwupdmgr get-history` is
empty, `/etc/modprobe.d/` has nothing camera-relevant, kernel cmdline is stock
(`ro quiet splash crashkernel=…`).
- * The PCH SPI controller (PCI 0000:00:1f.5, spi0) has one child for the BIOS
flash. spi-nor fails JEDEC identification on it ("unrecognized JEDEC id bytes:
f7 30 30 09 03 00"). I think this is unrelated.
- * There's an Intel USB-LJCA bridge (8086:0b63) at HS08 / INTC1098 that brings
up spi1 via spi_ljca. spi1 has no children (waiting_for_supplier=0). I'm not
sure if the VSC is supposed to live here on this platform.
+ So as best I can tell, the same kernel/firmware/userspace binaries that
+ worked on day one are now failing, without an apt-tracked change between
+ those two states. The HWE bump from .14 to .15 in my original report was
+ just the moment I noticed.
- I don't know what changed between the kernel I originally installed with
- and 7.0.0-14. apt history puts the HWE hop to 7.0.0-14.14 on 2026-04-23
- and nothing else camera-related changed in that transaction.
+ My best guess (and I'd love to be told if it's silly) is that this is a
non-deterministic probe ordering issue around the USB-LJCA bridge — the
INTC1096 ACPI companion is present at `\_SB_.PC00.XHCI.RHUB.HS08.VGPO` but its
GPIO chip never gets registered, so int3472 can't find it, so the rails never
come up, so VSC never starts, so streamon severs the link. I don't knw why this
would sometimes succeed and sometimes not on otherwise
+ identical software.
- Happy to do whatever is helpful my side to debug.
+ ACPI layout summary (full data in attached diagnostics):
- Attached `diagnostics.txt` has DMI, package versions, lsmod,
- lspci/lsusb, the spi_master tree, the relevant ACPI nodes, and the
- IPU6/MEI/VSC/OV2740/LJCA kernel and libcamera/pipewire log lines.
+ \_SB_.PC00.SPI1.SPFD HID INTC1094 (mei_vsc_hw match)
+ \_SB_.PC00.SPI1.SPFD.CVFD HID INTC1095
+ \_SB_.PC00.XHCI.RHUB.HS08.VGPO HID INTC1096 (GPIO chip never
registers)
+ \_SB_.PC00.XHCI.RHUB.HS08.VIC0/1 HID INTC1097
+ \_SB_.PC00.XHCI.RHUB.HS08.VSPI HID INTC1098
- ---
+ Side notes in case relevant:
- ProblemType: Bug
- ApportVersion: 2.34.0-0ubuntu2
- Architecture: amd64
- AudioDevicesInUse:
- USER PID ACCESS COMMAND
- /dev/snd/controlC0: atb 3887 F.... pipewire
- atb 3902 F.... wireplumber
- /dev/snd/seq: atb 3887 F.... pipewire
- CasperMD5CheckResult: pass
- CurrentDesktop: ubuntu:GNOME
- DistroRelease: Ubuntu 26.04
- InstallationDate: Installed on 2026-05-17 (2 days ago)
- InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64
(20260423.1)
- MachineType: LENOVO 21E8002YSG
- Package: linux (not installed)
- ProcEnviron:
- LANG=en_US.UTF-8
- PATH=(custom, no user)
- SHELL=/bin/bash
- TERM=xterm-256color
- XDG_RUNTIME_DIR=<set>
- ProcFB: 0 i915drmfb
- ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-15-generic
root=UUID=61e8b5c4-2752-445a-93d2-a68c8bb7dd3c ro quiet splash
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
- ProcVersionSignature: Ubuntu 7.0.0-15.15-generic 7.0.0
- RebootRequiredPkgs: Error: path contained symlinks.
- Tags: resolute wayland-session
- Uname: Linux 7.0.0-15-generic x86_64
- UpgradeStatus: No upgrade log present (probably fresh install)
- UserGroups: adm cdrom dip lpadmin lxd plugdev sudo users
- _MarkForUpload: True
- dmi.bios.date: 12/03/2025
- dmi.bios.release: 1.33
- dmi.bios.vendor: LENOVO
- dmi.bios.version: N3IET53W (1.33 )
- dmi.board.asset.tag: Not Available
- dmi.board.name: 21E8002YSG
- dmi.board.vendor: LENOVO
- dmi.board.version: SDK0T76530 WIN
- dmi.chassis.asset.tag: No Asset Information
- dmi.chassis.type: 10
- dmi.chassis.vendor: LENOVO
- dmi.chassis.version: None
- dmi.ec.firmware.release: 1.21
- dmi.modalias:
dmi:bvnLENOVO:bvrN3IET53W(1.33):bd12/03/2025:br1.33:efr1.21:svnLENOVO:pn21E8002YSG:pvrThinkPadX1NanoGen2:rvnLENOVO:rn21E8002YSG:rvrSDK0T76530WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21E8_BU_Think_FM_ThinkPadX1NanoGen2:pfaThinkPadX1NanoGen2:
- dmi.product.family: ThinkPad X1 Nano Gen 2
- dmi.product.name: 21E8002YSG
- dmi.product.sku: LENOVO_MT_21E8_BU_Think_FM_ThinkPad X1 Nano Gen 2
- dmi.product.version: ThinkPad X1 Nano Gen 2
- dmi.sys.vendor: LENOVO
+ * The PCH SPI controller (PCI 0000:00:1f.5, spi0) has one child for the BIOS
flash; spi-nor fails JEDEC ID on it. I think this is unrelated.
+ * The Intel USB-LJCA bridge (8086:0b63) at HS08 / INTC1098 brings up spi1 via
`spi_ljca`; `spi1` has no children (`waiting_for_supplier=0`).
+ * I have not tried a 6.x kernel and many other distros — my recollection is
the camera also did not work on 6.x for me even with the Intel patches, so I
don't think rolling back further is productive.
+
+ Attached `diagnostics.txt` (filed initially against 7.0.0-15) and
+ `diagnostics-7.0.0-14.txt` (captured today on 7.0.0-14) have DMI, package
versions, lsmod, lspci/lsusb, the spi_master tree, the relevant ACPI nodes, and
the IPU6/MEI/VSC/OV2740/LJCA kernel and libcamera/pipewire log lines.
+
+ They're the same shape so they can be diffed directly.
+
+ Happy to do whatever's useful: capture across cold-boot/warm-
+ boot/suspend cycles, watch whether the INTC1096 GPIO chip ever registers
+ across multiple boots, try unbinding/rebinding `usb_ljca`, or run with
+ debug options on `int3472`/`mei_vsc`/`gpio_ljca`.
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https://bugs.launchpad.net/bugs/2153096
Title:
IPU6 webcam (OV2740) on X1 Nano fails on kernel 7.0.0-14/-15: int3472
cannot find GPIO chip INTC1096:00, VSC chain doesn't come up
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